Risk Assessment Of The Debris Flow Gully At Pingyuan Village Of Mentougou Distract In West Of Beijing

Risk assessment of debris flow disaster is the foundation and basis of debris flow disaster prevention and mitigation work,and it is essential for risk control and disaster management.Therefore,debris flow disaster domestic and international researchers have attached great importance to the research of this subject.This thesis carried out the debris flow risk assessment on a single gully at Pingyuan village of Tanzhesi town in Mentougou distract in Beijing.Based on the assessment,it established the debris flow risk management system of Pingyuan village gully.Study contents and achievements acquired in the thesis are mainly includes as follows:(1)The cause of Pingyuan village gully debris flow is mainly due to human activities.Based on the comprehensive analysis of domestic and international risk assessment of debris flow,this thesis introduced the natural geographical and geological conditions of debris flow gully in detail.The emphases of this study are human engineering activities and social and economic conditions.(2)The thesis analysis of the formation conditions of this debris flow in depth,three formation conditions are landform,rainfall,loose material conditions,none of which can be omitted.(3)According to the geological environmental conditions within the basin,the thesis analysis and calculated the movement characteristics of Pingyuan village gully debris flow,with the method of provided by empirical formula and technical specifications.The value of characteristic parameters in different frequency condition through calculation are acquired,which includes severe,flow velocity,peak flow,size,the overall impact,climb and maximum lifting height of the debris flow.(4)The debris flow risk assessment is combined with the three aspects,debris flow hazard assessment,vulnerability assessment and risk assessment.With the quantitative comprehensive evaluation method,the respectively using of Analytic Hierarchy Process and the method of Liu Xilin single debris flow hazard assessment for risk assessment,and comparative analysis of these two kinds of methods,the outcome are 0.39 and 0.51,which belong to medium hazard.Using the general formula method for the debris flow vulnerability assessment,the outcome is 0.66,which belong to vulnerability.The final risk assessment results are 0.32 and 0.34,both of which belong to medium risk.(5)At the end of this thesis,Pingyuan village gully debris flow risk management system is established on the basis of the research before,including risk analysis,risk control measures and emergency response mechanism.The system will provide a scientific basis to the debris flow control in Pingyuan village.